1. Field of the Invention
This invention relates to a moving coil pickup cartridge and, in particular, to the grounding of the magnetic circuit for such a cartridge.
2. Discussion of the Prior Art
As shown in FIG. 1, a moving coil type pickup cartridge may include an armature 3 having a generator coil 2 wound thereabout. The rear of a cantilever 1 is joined at the center of the armature, the cantilever having a stylus tip at its front end. A ring-shaped damper 5 is placed between armature 3 and a pole piece 4 and the unit is held in place by a stopper 6 formed within the cantilever, a stopper 6' inserted and fixed in pole piece 4, and suspension wire 7. The magnetic circuit for the cartridge is comprised of a magnet 8, a rear yoke 9, pole piece 4, armature 3, and front yoke 10. Output voltage is induced in generator coil 2 by rotation of armature 3 during record reproduction, the coil output being applied to output terminals 11 comprising hot terminal H and ground terminal G. Since the space between the generator coil and armature is, in essence, insulated, the metal parts of the main structure including armature 3 must be electrostatically equipotential with generator coil 2 in order to eliminate capacitance and inductance generated in space. Consequently, measures have been taken to ground the magnetic circuit by connecting the ground line G of output terminals 11 to the rear end of pole piece 4 or rear yoke 9 as shown in FIG. 1. These measures have been taken to improve the reproduced sound quality response and the high frequency range.